The present invention relates to a blower for a motor. More particularly, the present invention relates to a blower that is integrally-formed as part of a motor that drives a compressor.
Motors are often used to drive compressors to produce a flow of compressed fluid. When used to drive a centrifugal compressor, the motor must rotate at a relatively high speed (e.g., greater than 30,000 RPM) to efficiently drive the compressor. In addition, it is desirable to employ a variable speed motor to allow for more accurate and efficient control of the quantity of compressed fluid produced. High power-density permanent magnet motors are well suited to driving centrifugal compressors. However, accurate and reliable temperature control within the housing of the high-speed, high power-density permanent magnet electric motor is needed to inhibit loss of magnetic properties of the core, damage to the electric insulation of the stator, and the malfunction of the rotor-bearing system.
Prior air cooled motors often employed a separate blower that directed air through the motor. The separate blower, driven by a separate motor, was generally required as the speed of the permanent magnet motor is too high to employ a directly-driven fan. However, the use of the second motor to drive the blower can be problematic if the motor or the blower fail during operation of the permanent magnet motor. Such a failure could reduce or eliminate the flow of cooling air which might result in motor overheating.